Cannot load movie files on Ubuntu
I solved, after two months from when the problem occurred. I used the irc chat and three or four forums and, of course, Google.
The page that helped me a lot is https://developer.blender.org/T28790
where it says that is a problem of ffmpeg with the compiling of GCC. You can solve that downloading the precompiled version here https://builder.blender.org/download/
It doesn't work if you compile the version and also the repository one does not work.

I answered my question to help all the people that will have the same problem =)